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Interaction Between Corticosteroids and Presynaptic-Acting Toxins from Snake Venoms in Rat Phrenic Nerve Terminals

  • H. Van Wilgenburg
  • R. S. Leeuwin
  • K. D. Njio
  • R. D. Veldsema-Currie
Part of the Topics in the Neurosciences book series (TNSC, volume 1)

Abstract

Corticosteroids and the toxins beta-Bungarotoxin (beta-BuTx) and the angusticeps-type “F7”-toxin from snake venoms all affect neuromuscular transmission at the presynaptic site of the motor- endplate in rodent nerve-muscle preparations (1,2). Prednisolone and dexamethasone (Dex), in low concentrations, increase the amplitude of the miniature endplate potentials (MEPPs) without affecting the rate of transmitter release (3). On the other hand beta-BuTx causes, after an initial decrease followed by an increase of MEPP frequency, failure of transmitter release (4). The polypeptide “F7” one of the components of the venom of the green mamba, Dendroaspis angusticeps, augments acetylcholine release (5). These effects of the corticosteroids, beta-BuTx and “F7” toxin on acetylcholine release only occur after a latent period of 30 to 60 min, suggesting that in each case an indirect mechanism is involved.

Keywords

Snake Venom Transmitter Release Acetylcholine Release MEPP Amplitude Amplitude Histogram 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Veldsema-Currie RD, Van Wilgenburg H, Labruyere WT, Langemeijer MWE: Presynaptic, facilitatory effects of the corticosteroid dexamethasone in rat diaphragm: Modulation by beta-Bungarotoxin. Brain Research 294: 315–325, 1984.PubMedCrossRefGoogle Scholar
  2. 2.
    Lee CY, Tsaur ML, Tsai MC, Carlsson FHH, Joubert FJ: Facilitation of acetylcholine release by Angusticeps-type toxins from Mamba venoms. Neuroscience Letters, Suppl. 14: S215, 1983.Google Scholar
  3. 3.
    Van Wilgenburg H, Njio KD, Belling GAC, Van Den Hoven S: Effects of corticosteroids on the myoneural junction. A morphometrlc and electrophysiological study. Europ. J. Pharmacol. 84: 129–137, 1982.CrossRefGoogle Scholar
  4. 4.
    Howard BD, Gundersen CB: Effects and mechanisms of polypeptide neurotoxins that act presynaptically. Ann. Rev. Pharm. Toxicol. 20: 307–366, 1980.PubMedCrossRefGoogle Scholar
  5. 5.
    Viljoen CC, Botes DP: Snake venom toxins. The purification and amino acid sequence of toxin F VII from Dendroaspis angusticeps venom. J. Biol. Chem. 248: 4915–4919, 1973.PubMedGoogle Scholar
  6. 6.
    Van Wilgenburg H: The effect of prednisolone on neuromuscular transmission in the rat diaphragm. Europ. J. Pharmacol. 55: 355–361, 1979.CrossRefGoogle Scholar
  7. 7.
    Warmolts JR, Engel WK, Whitaker JN: Alternate day prednisolone in a patient with myasthenia gravis. Lancet 2: 1198–1199, 1970.PubMedCrossRefGoogle Scholar
  8. 8.
    Wolters ECMJ, Leeuwin RS: The effect of corticosteroids on the nerve-diaphragm preparation treated with hemicholinium-3, a possible model for myasthenia gravis. Neurology 26: 574–578, 1976.PubMedGoogle Scholar
  9. 9.
    Veldsema-Currie RD, Wolters ECMJ, Leeuwin RS: The effect of corticosteroids and hemicholinium-3 on choline uptake and incorporation into acetylcholine in rat diaphragm. Europ. J. Pharmacol. 35: 399–402, 1976.CrossRefGoogle Scholar
  10. 10.
    Flower RJ, Blackwell GJ: Anti-inflammatory steroids induce biosynthesis of a phospholipase A2 inhibitor which prevents prostaglandin generation. Nature (Lond.) 278: 456–459, 1979.CrossRefGoogle Scholar
  11. 11.
    Chang CC, Lee CY: Isolation of neurotoxins from the venoms of Bungarus multicinctus and their modes of neuromuscular blocking action. Arch. Int. Pharmacodyn. 144: 241–257, 1963.PubMedGoogle Scholar
  12. 12.
    Baxter JD, Rousseau GG: Glucocorticoid hormone action. Springer Berlin, 1979, pp1–24.Google Scholar
  13. 13.
    Llados F, Matteson DR, Kriebel ME: Beta-Bungarotoxin preferentially blocks one class of miniature endplate potentials. Brain Research 192: 598–602, 1980.PubMedCrossRefGoogle Scholar
  14. 14.
    Harvey AL, Karlsson E: Protease inhibitor homologues from mamba venoms: facilitation of acetylcholine release and interactions with prejunctional blocking toxins. Brit. J. Pharmacol. 77: 153–161, 1982.Google Scholar
  15. 15.
    Veldsema-Currie RD, Njio KD, Van Wilgenburg H, Leeuwin RS, Lee CY: Alterations in ultrastructure and activity of motor nerve terminals caused by “F7” toxin from the eastern green Mamba snake (Dendroaspis angusticeps). In preparation.Google Scholar
  16. 16.
    Lee CY, Lin WW, Carlsson FHH, Joubert FJ: Anticholinesterase activity of Angusticeps-type toxins and protease inhibitor homologues from Mamba venoms. Chin. J. Physiol. 27: 20A, 1984.Google Scholar

Copyright information

© Martinus Nijhoff Publishing, Boston 1986

Authors and Affiliations

  • H. Van Wilgenburg
    • 1
  • R. S. Leeuwin
    • 1
  • K. D. Njio
    • 1
  • R. D. Veldsema-Currie
    • 1
  1. 1.Dept. of PharmacologyUniversity of AmsterdamAmsterdamThe Netherlands

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